System and method for filter enhancement

ABSTRACT

A system for filter enhancement, preferably including one or more analog taps and a controller, and optionally including one or more couplers. The system is preferably configured to integrate with a filter, such as a passband filter or other frequency-based filter. The system can be configured to integrate with an RF communication system, an RF front end, or any other suitable RF circuitry. A method for filter enhancement, preferably including configuring one or more analog taps, and optionally including calibrating a system for filter enhancement and/or receiving temperature information.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of U.S. Provisional Application Ser.No. 63/298,934, filed on 12 Jan. 2022, which is incorporated in itsentirety by this reference.

TECHNICAL FIELD

This invention relates generally to the filters field, and morespecifically to a new and useful system and method for filterenhancement.

BRIEF DESCRIPTION OF THE FIGURES

FIG. 1A is a schematic representation of an embodiment of a system forfilter enhancement.

FIG. 1B is a schematic representation of an example of the systemintegrated with a filter.

FIG. 1C is a schematic representation of a specific example of thesystem.

FIGS. 2A-2B are schematic representations of a first and second example,respectively, of an analog tap of the system.

FIG. 3 is a schematic representation of an example of a switchable delayof the system.

FIG. 4 is a schematic representation of an example of a controller ofthe system.

FIG. 5 is a schematic representation of an example of a coupler of thesystem.

FIG. 6 is a schematic representation of an embodiment of a method forfilter enhancement.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

The following description of the preferred embodiments of the inventionis not intended to limit the invention to these preferred embodiments,but rather to enable any person skilled in the art to make and use thisinvention.

1. Overview

A system 100 for filter enhancement preferably functions to enhanceperformance of a filter (e.g., passband filter). The system 100preferably includes one or more analog taps 110 and a controller 120,and can optionally include one or more couplers 130 (e.g., as shown inFIG. 1A). However, the system 100 can additionally or alternativelyinclude any other suitable elements in any suitable arrangement.

The system 100 is preferably configured to integrate with a filter 90.The filter 90 is preferably a frequency filter (e.g., configured to passsignals within one or more passbands and/or attenuate signals in one ormore stopbands), more preferably a passband filter, but can additionallyor alternatively include any other suitable filters. The filter 90 ispreferably an analog filter, but can additionally or alternativelyinclude a digital filter and/or any other suitable filters. In specificexamples, the filter 90 can include a BAW filter, a SAW filter, aceramic filter, a discrete LC filter, and/or any other suitable filtertypes. In some embodiments, the filter 90 can be arranged along aprimary signal path, and the system 100 can be coupled (or configured tobe coupled) to the primary signal path in parallel with the filter 90(e.g., as shown in FIG. 1B); however, the filter 90 and system 100 canhave (or be configured to have) any other suitable coupling relative toeach other. In some examples, the system 100 can optionally beconfigured to integrate with a radio frequency (RF) communication systemor any suitable elements thereof, such as an RF front end. For example,the system 100 can be configured to integrate with a front end includingthe filter 90, one or more power amplifiers, and/or any other suitableelements.

The system 100 is preferably defined as and/or in one or more integratedcircuits (ICs). In a first example, the system 100 (or a subset thereof)is defined in an IC (e.g., packaged as a chip) configured to be coupledto the filter 90 (e.g., coupled to the primary signal path in parallelwith the filter 90). In a second example, the system 100, or a subsetthereof, along with one or more elements of an RF communication system(e.g., the filter 90, other RF elements, the entire RF front end, etc.)are defined together in a single IC (e.g., packaged as a chip) and/ordefined in neighboring ICs (e.g., co-packaged ICs). However, the system100 can additionally or alternatively be defined in any other suitablemanner.

A method 200 for filter enhancement is preferably performed using thesystem 100 described herein. The method 200 preferably functions tocontrol the system 100 to enhance performance of the filter 90 (e.g., toreduce or eliminate temperature dependence of the filter 90, to createor enhance attenuation within one or more stopbands defined by thefilter 90 and/or any suitable subset thereof, etc.). The method 200preferably includes configuring one or more analog taps S230, and canoptionally include calibrating the system S210 and/or receivingtemperature information S220 (e.g., as shown in FIG. 6 ). However, themethod can additionally or alternatively include any other suitableelements performed in any suitable manner.

2. Benefits

Variants of the technology (e.g., the system 100 and/or method 200) canconfer one or more benefits.

First, in some variants, the technology can enable isolation ofdifferent transmissions (e.g., frequency-multiplexed transmissions),such as in cellular networks and/or Wi-Fi communication schemes. Forexample, variants of the technology can enable and/or enhance isolationin networks using Wi-Fi communication schemes, such as Wi-Fi 4, 5, 6, 7,and/or other generations (e.g., communication schemes codified in one ormore IEEE 802.11 standards, such as 802.11a, 802.11b, 802.11g, 802.11n,802.11ac, 802.11ax, and/or 802.11be, each of which are hereinincorporated in their entireties by this reference).

Second, variants of the technology can avoid and/or reduce the need forcomplicated impedance matching, and/or can significantly reduceinsertion losses, as compared with systems including a seriesarrangement of multiple filters (e.g., passband filters).

Third, variants of the technology can reduce system complexity, expense,and/or insertion losses as compared with parallel arrangements ofmultiple filters (e.g., passband filters), such as switched arrangementsenabling selection of one out of a plurality of different filters. Insome examples, the number of filters in a filter bank with parallelfilters (e.g., passband filters) may be reduced (or alternatively, thefilter bank may be replaced by a single filter), due to performanceenhancement of some or all filters of the filter bank by use of thetechnology.

Fourth, variants of the technology can enable cancellation and/orreduction of filter temperature dependences. For example, variants ofthe technology can enable maintenance of the filter skirt at or near adesired frequency and/or slope, such as through dynamic tuning of one ormore analog taps in response to changes in temperature and/or changes infilter response.

Fifth, variants of the technology can enable the creation and/orenhancement of one or more high-attenuation stopbands (e.g., past thefilter edge). In a first example, one or more analog taps of thetechnology can be used to extend a stopband from the filter skirt. In asecond example, one or more analog taps of the technology can be used toenhance attenuation farther from the skirt (e.g., within, such ascentered in, a neighboring transmission band).

Sixth, variants of the technology can enable autonomous enhancement offilter performance. For example, the use of one or more sensors (e.g.,temperature sensors) coupled with logic that determines analog tapsettings based on the sensor readings (e.g., based on one or more lookuptables indexed by the sensor readings) can enable dynamic tuning of theanalog tap(s) in response to changing circumstances (e.g., changingtemperature).

However, variants of the technology can additionally or alternativelyconfer any other suitable benefits, and/or can confer no such benefits.

3. System 3.1 Analog Taps

The system 100 preferably includes one or more analog taps 110, such asincluding a plurality of analog taps (e.g., 2, 3, 4, or more analogtaps), such as shown by way of example in FIGS. 1A-1C. Each analog tappreferably functions to perform filter enhancement (e.g., temperaturedependence reduction, stopband enhancement, etc.) within a desiredfrequency band (e.g., wherein each analog tap can be responsible forfilter enhancement within a different frequency band). In examplesincluding a plurality of analog taps, the different analog taps arepreferably arranged in parallel within the circuit (e.g., wherein eachanalog tap is electrically coupled in parallel with all the other analogtaps and with the filter 90).

Each analog tap preferably includes one or more scalers 111, phaseshifters 112, delays 113, tap filters 114, and/or coupling tuners 115(e.g., as shown in FIGS. 1C and/or 2A-2B), and can additionally oralternatively include any other suitable elements. A person of skill inthe art will recognize that the scaler(s), phase shifter(s), delay(s),filter(s), coupling tuner(s), and/or any other suitable elements can bearranged in any suitable order within the analog tap (e.g., orderrelative to signal propagation through the analog tap); for example, ascaler can be arranged before the phase shifter (e.g., wherein theanalog tap first scales and then phase shift signals propagating throughthe analog tap) and/or after the phase shifter (e.g., wherein the analogtap first phase shifts and then scales signals propagating through theanalog tap).

The scaler 111 preferably functions to scale (e.g., attenuate and/oramplify) the amplitude of the signal propagating through the analog tap.Each scaler is preferably an attenuator (e.g., configured to attenuatesignal intensity), but can additionally or alternatively include anamplifier (e.g., configured to amplify signal intensity) and/or anyother suitable scaling element. The scaler is preferably operable to beconfigured between different scaling factors, such as operable to becontrolled throughout a continuum of possible scale values (e.g.,operable to scale the propagating signal by any factor between 1 and aminimum value, such as 0.1, 0.03, 0.01, etc.); however, the scaler canadditionally or alternatively be operable to switch between a pluralityof different scaling elements (e.g., fixed scaling elements, such asresistors of fixed resistance). In some examples, the analog tap caninclude a plurality of scalers (e.g., attenuators), such as a firstscaler upstream of the phase shifter and a second scaler downstream ofthe phase shifter; in some examples, such use of multiple scalers canfunction to increase the scaling range achievable by the analog tap(e.g., by the plurality of scalers). However, the analog taps canadditionally or alternatively include any other suitable scalers.

The phase shifter 112 preferably functions to shift the phase of thesignal propagating through the analog tap. The phase shifter ispreferably operable to be configured between different phase shiftamounts, such as operable to be controlled throughout a continuum ofpossible phase shift values (e.g., operable to shift the phase of thepropagating signal by any value between 0 and a maximum value, such as2π, π, π/2, or π/4 radians, etc.); however, the phase shifter canadditionally or alternatively be operable to switch between a pluralityof different phase shift elements (e.g., fixed phase shift elementsconfigured to impose a fixed amount of phase shift on all signals).However, the analog taps can additionally or alternatively include anyother suitable phase shifters.

The delay 113 preferably function to delay the signal propagatingthrough the analog tap. The delay is preferably operable to beconfigured between different delay times. In a first variant, the delayis operable to be controlled throughout a continuum of possible delayvalues (e.g., operable to delay the propagating signal by any valuebetween a minimum value, such as 0 or a value greater than zero, and amaximum value). In a second variant, the delay is operable to switchbetween a plurality of different delay elements (e.g., each configuredto impose a different amount of delay time), such as switching betweenone or more fixed delay values and/or substantially zero delay.

In some examples, the switchable delay includes a plurality of delaysegments (e.g., meandering traces) and a switch network operable toenable or disable each delay segment independently (e.g., wherein, foreach delay segment, the switch network preferably defines a bypass paththat, when the switch network is configured appropriately, is operableto carry signals in a manner that bypasses the delay segment, such aswherein the bypass path includes a plurality of bypass segments, oneassociated with each delay segment and operable to carry signals in amanner that bypasses the associated delay segment). Each delay segmentis preferably associated with (e.g., configured to impose) a differentamount of delay time (e.g., wherein each delay segment defines adifferent signal propagation pathlength, such as having a trace meanderof a different length).

In some such examples, a simple switch network to enable or disable eachdelay segment could allow undesired resonances to arise (e.g., fromsignal coupling into unused branches of the switch network). To avoidsuch undesired resonances, the switchable delay preferably includesmultiple switches for each delay segment, thereby enabling isolation ofunused segments from the circuit. For example, the switchable delay caninclude three switches (e.g., single-pole single-throw switches) foreach delay segment (e.g., as shown in FIG. 3 ), thereby ensuring thatsignals are not coupled into unused delay segments (nor into unusedbypass paths).

However, the delay can additionally or alternatively be operable toimpose a fixed delay and/or be operable in any other suitable manner,and/or the analog taps can additionally or alternatively include anyother suitable delays.

The tap filter 114 preferably functions to define a frequency range inwhich the analog tap affects (and/or does not affect) performance of thefilter 90. For example, the tap filter 114 can function to isolate theperformant frequency region of the analog tap (e.g., removing frequencyregions that detract from, rather than enhance, filter 90 performance,and/or that otherwise may introduce undesired filter 90 performancecharacteristics). The tap filter 114 preferably performs frequency-basedfiltering (e.g., wherein the filter can include a high-pass filter,low-pass filter, band-pass filter, etc.). The tap filter cutofffrequency (or frequencies) is preferably tunable (e.g., enablingconfiguration of the location of the passband). Additionally oralternatively, the tap filter slope is preferably tunable and/orotherwise configurable. For example, the tap filter can include aplurality of filter stages, wherein one or more of the stages can bebypassed (e.g., a tap filter including two filter stages, such as withthree filter poles per stage, wherein one of these filter stages can bebypassed for a low-slope configuration). The tap filter can optionallybe operable to switch between different filter modes. For example, thetap filter can be operable to switch between two or more of a high-passfilter mode, a low-pass filter mode, a band-pass filter mode, a bypassmode in which no, or substantially no, filtering is performed, and/orany other suitable modes. However, the tap filter 114 can additionallyor alternatively have any other suitable characteristics.

The coupling tuner 115 preferably functions to tune signal coupling tothe analog tap (e.g., coupling into and/or out of the analog tap, suchas from and/or to the primary signal path respectively). The couplingtuner preferably tunes coupling into the analog tap (and canadditionally or alternatively function to reduce insertion lossassociated with the tap, such as by reducing signal coupling into theanalog tap in situations in which higher signal intensity is notrequired within the tap). The coupling tuner can additionally oralternatively function to increase overall signal scaling range (e.g.,as the signal can be scaled both by the coupling tuner 115 and thescaler 111). For example, coarse attenuation can be provided by thecoupling tuner 115, followed by fine tuning of attenuation at the scaler111. The coupling tuner 115 preferably includes one or more capacitiveelements (e.g., tunable capacitors), and can additionally oralternatively include one or more resistive elements (e.g., tunableresistors). However, the coupling tuner 115 can additionally oralternatively include any other suitable elements in any suitablearrangement.

As described above, some or all components of the analog taps (e.g.,scalers 111, phase shifters 112, delays 113, tap filters 114, couplingtuners 115, etc.) are preferably configurable (e.g., operable to alterone or more operational characteristics, such as scaling factor, phaseshift amount, delay time, etc.). Such configurability can be achieved byuse of tunable elements (e.g., voltage-controlled elements,current-controlled elements, manually-tunable elements, etc.), by use ofswitched banks of separate elements (e.g., switched banks of non-tunableelements), and/or in any other suitable manner. However, any or all ofthe components of the analog taps (and/or any suitable characteristicsthereof) can alternatively be fixed and/or have any other suitableproperties.

In a first example (e.g., as shown in FIG. 2A), an analog tap 110includes a series arrangement of elements that includes, in order fromupstream to downstream: an upstream input (e.g., that functions toreceive signals coupled into the analog tap from the primary signal pathupstream of the filter 90), followed by a coupling tuner 115 (e.g.,including a tunable capacitor, optionally followed by a tunableresistor), followed by a phase shifter 112 (e.g., tunable phaseshifter), followed by a scaler 111 (e.g., tunable resistive attenuator),followed by a tap filter 114 (e.g., high-pass filter or low-pass filter,preferably configurable to adjust the filter slope and/or cutofffrequency), followed by a delay 113 (e.g., tunable or switchable delay),followed by a downstream output (e.g., which functions to provide signalfor coupling back into the primary signal path downstream of the filter90).

In a second example (e.g., as shown in FIG. 2B), an analog tap includesa series arrangement of elements that includes, in order from upstreamto downstream: an upstream input (e.g., as described above regarding thefirst example), followed by a coupling tuner 115 (e.g., including atunable resistor), followed by a phase shifter 112 (e.g., tunable phaseshifter), followed by a scaler 111 (e.g., including a tunable resistiveattenuator), followed by a tap filter 114 (e.g., as described aboveregarding the first example), optionally followed by a delay 113 (e.g.,tunable or switchable delay), followed by a coupling tuner 115 (e.g.,including a tunable capacitor), followed by a downstream output (e.g.,as described above regarding the first example).

However, each analog tap 110 can additionally or alternatively includeany suitable elements in any suitable arrangement.

3.2 Controller

The controller 120 preferably functions to control operation of theanalog taps (e.g., to enhance performance of the filter 90, to performthe method 200 such as described below in more detail, etc.). Forexample, the controller can function to configure each tunable elementof the taps (e.g., scalers, phase shifters, delays, filters, couplingtuners, etc.) and/or any suitable subset thereof.

The controller 120 preferably includes one or more temperature sensors121 and control logic 123, and can optionally include one or moreanalog-to-digital converters (ADCs) 122, communication interfaces 124,and/or power handling elements 125 (e.g., as shown in FIG. 1C and/orFIG. 4 ). However, the controller 120 can additionally or alternativelyinclude any other suitable elements in any suitable arrangement.

The temperature sensor 121 preferably functions to sample thetemperature of the system 100, the filter 90, and/or any other suitableelements (e.g., other locations near the system 100, filter 90, and/orassociated elements). The temperature sensor is preferably colocatedwith the analog taps 110 (e.g., arranged on the same chip and/or withinthe same chip package as the analog taps), but can additionally oralternatively have any other suitable arrangement. In some examples, thecontroller can optionally include multiple temperature sensors arrangedin different locations. The controller can additionally or alternativelyinclude one or more inputs configured to receive information (e.g.,information indicative of temperature measurements) from one or moreremote temperature sensors, such as temperature sensors of an RFcommunication system (e.g., temperature sensors colocated with thefilter 90 and/or having any other suitable arrangement).

The ADC 122 can function to convert a temperature sensor signal intodigital temperature information. For example, the ADC 122 can include aflash ADC configured to compare a temperature sensor signal to one ormore reference signals and output information (e.g., digital signal)representative of a temperature or temperature difference.

The control logic 123 preferably functions to determine appropriateconfigurations for the elements of the analog taps. The control logicpreferably performs this determination based on temperature information(e.g., and/or based on pre-loaded data, such as data stored in OTPmemory), but can additionally or alternatively perform the determinationbased on any other suitable information.

The control logic preferably includes one or more lookup tables (e.g.,in one-time programmable (OTP) memory). The lookup tables are preferablyindexed based on temperature (e.g., based on the temperature ortemperature difference signal received from the ADC 122). Each bin(e.g., temperature bin) of a lookup table can include desired settingsfor each configurable element of the analog taps (and/or for anysuitable subset thereof).

In some examples, the control logic can include multiple lookup tables.In some such examples, the different lookup tables can be associatedwith different high-level settings (e.g., different desired effects foreach analog tap, such as filter edge temperature stabilization versusfilter skirt extension stopband enhancement versus neighboring bandstopband enhancement; different filters and/or filter characteristics,such as having one or more lookup tables for each filter SKU; etc.).Additionally or alternatively, the control logic can include the abilityto transition between the multiple different lookup tables based ondifferent temperature scenarios (e.g., enabling correction fornon-linear temperature dependence, such as piecewise linear temperaturedependence having a changing corner frequency). However the multiplelookup tables can additionally or alternatively be used in any othersuitable manner, and/or the control logic can alternatively include onlya single lookup table.

In some examples, the control logic can include hysteresis logic (e.g.,configured to prevent rapid cycling between different configurations,such as setting the threshold for transitioning into a lower temperaturebin at a slightly lower temperature than the thresholds fortransitioning out of that lower temperature bin into the highertemperature bin). However, the control logic can additionally oralternatively perform any other suitable smoothing, and/or can beconfigured to control the analog taps in any other suitable manner.

In a first example, the control logic includes one or more lookup tablesdetermined after integration of the system 100 with a filter 90 (and/orassociated RF communication system), such as wherein the lookup tablesare determined based on the thermal behavior of the specific integratedassembly (e.g., offsets between temperatures measured at the temperaturesensor 121 and temperatures experienced at the filter 90, offsetsaccounting for correlations between temperatures measured at thetemperature sensor 121 and behavioral effects such as frequency shiftsexhibited by the filter 90, etc.).

In a second example, the lookup tables can be determined based onstandard and/or expected behavior of a type of filter 90 (e.g., aparticular filter model) and/or RF communication system, such as basedon the expected thermal behavior of the filter 90, the RF communicationsystem, and/or the integrated assembly. In this example, the controllogic can additionally or alternatively include one or more processoffset settings, which can be determined based on specificcharacteristics of the system 100, the filter 90, the RF communicationsystem, and/or any other suitable elements (e.g., configured to accountfor manufacturing process variation, such as in tunable elements of thesystem and/or other elements, piezoelectric thickness of a BAW filter90, etc.). For example, these process offset settings can be used tooffset the relationship between temperature information received fromthe temperature sensor (e.g., via the ADC) and the lookup table (e.g.,wherein a process offset of plus one can result in looking up a bin onegreater than typical for a given input temperature information).

However, the control logic 123 can additionally or alternatively includeany other suitable elements configured in any other suitable manner.

The controller 120 can optionally include one or more communicationinterfaces 124, which can function to enable remote inputs to and/orcontrol of the controller (e.g., providing alternate lookup tables foruse by the controller). In one example, the communication interface caninclude a serial peripheral interface (SPI). However, the controller canadditionally or alternatively include any other suitable communicationinterfaces 124.

The controller 120 can optionally include one or more power handlingelements 125. For example, the controller can include a power input(e.g., operable to receive electrical power, such as from an RFcommunications system into which the system is integrated), a powerregulator (e.g., operable to deliver electrical power to other elementsof the system, such as via one or more positive bias rails), and/or anegative bias element (e.g., operable to provide a negative bias toother elements of the system, such as via one or more negative biasrails) such as a charge pump. The power received at the power input ispreferably provided to other elements of the system via the powerregulator and/or the negative bias element, but can additionally oralternatively be used in any other suitable manner. However, thecontroller can additionally or alternatively include any other suitablepower handling elements.

Additionally or alternatively, the system 100 can include one or moreanalog taps with fixed (or substantially fixed) configurations, whereinsuch a system can optionally omit the controller 120 (e.g., wherein theanalog taps can be pre-configured with a fixed configuration, and so nocontroller is needed).

3.3 Couplers

The couplers 130 preferably function to couple signals into and/or outof the system 100 (e.g., between the primary signal path and thesystem). For example (e.g., as shown in FIG. 1B), the system 100 caninclude: a first coupler 130 a configured to couple signals from theprimary signal path (e.g., upstream of the filter 90) into the system100, and a second coupler 130 b configured to couple signals (e.g., thesignals coupled into the system by the first coupler, after propagationthrough the analog taps) from the system 100 onto the primary signalpath (e.g., downstream of the filter 90, such that the coupled signalsbypass the filter 90).

In some examples, a coupler 130 can include (e.g., be) a short sectiondirectional transmission line coupler, but can additionally oralternatively include (e.g., be) any suitable power divider, powercombiner, directional coupler, and/or other type of signal splitter. Thesignal coupler 130 is preferably a passive coupler, but may additionallyor alternatively be an active coupler (for instance, including poweramplifiers). In some examples, the coupler 130 can include: a coupledtransmission line coupler, a branch-line coupler, a Lange coupler, aWilkinson power divider, a hybrid coupler, a hybrid ring coupler, amultiple output divider, a waveguide directional coupler, a waveguidepower coupler, a hybrid transformer coupler, a cross-connectedtransformer coupler, a resistive tee, and/or a resistive bridge hybridcoupler.

In one example, the coupler 130 can include an inductor 131 coupling theprimary signal path to ground and a capacitor 132 coupling the primarysignal path to the system (e.g., as shown in FIG. 5 ). In a variation ofthis example (e.g., in which each analog tap includes a coupling tuner115 with a capacitor), the capacitor 132 can be omitted (e.g., whereinthe coupling tuners 115 can function as a capacitive coupling betweenthe primary signal path and the system).

However, the system can additionally or alternatively include any othersuitable couplers.

Further, the system can additionally or alternatively include any othersuitable elements in any suitable arrangement.

4. Method 4.1 Calibrating The System

Calibrating the system S210 can function to determine and/or providecalibration information (e.g., temperature lookup tables) for systemoperation. S210 is preferably performed once (e.g., at the start ofmethod performance and/or at any other suitable time; during systemdesign, fabrication, testing, and/or integration such as integrationwith the filter 90 and/or RF communication system, etc.); however, S210can additionally or alternatively be performed at any other suitabletime(s) and/or performed any suitable number of times.

In some examples, S210 can be performed based on specificationsassociated with the system 100 and/or RF communication system (e.g.,filter 90), such as performed in advance of integration of the system100 with the filter 90 and/or the RF communication system.

Additionally or alternatively, S210 can be performed based on actualsystem 100 and/or RF communication system (e.g., filter 90)characteristics (e.g., wherein S210 is performed during and/or afterintegration of the system with the filter and/or RF communicationsystem, such as performed based on observed behavior of the integratedassembly, such as temperature characteristics thereof).

S210 preferably includes storing calibration information, such asstoring one or more lookup tables (e.g., temperature-indexed lookuptables) in OTP memory of the controller. In some examples, the lookuptables can additionally or alternatively be indexed based on delayconfiguration (e.g., delay time(s) associated with one or more variabledelays, switch settings of one or more switchable delays, etc.),frequency parameters (e.g., cutoff frequency and/or slope for one ormore tap filters, actual and/or desired passband frequencies for one ormore filters 90, etc.), and/or any other suitable parameters associatedwith system operation. For example, system operation may dictatechanging a delay configuration (e.g., switching from a first delay timeto a second delay time); in response to such a change, one or more otheranalog tap configuration parameters may also be changed, such as whereinthe lookup table(s) dictating these configuration parameters areselected and/or indexed based on the delay configuration (e.g., inaddition to being indexed based on temperature). Additionally oralternatively, S210 can include pre-configuring tunable elements,pre-selecting fixed elements, and/or pre-configuring the system in anyother suitable manner.

However, S210 can additionally or alternatively include calibrating thesystem in any other suitable manner. Further, S210 can additionally oralternatively be performed with any other suitable timing and/orperformed based on any other suitable information.

4.2 Receiving Temperature Information

Receiving temperature information S220 can function to provide an inputto the controller lookup tables (e.g., thereby enabling reduction and/orelimination of filter temperature dependences). The temperatureinformation is preferably received from one or more temperature sensorsof the system (but can additionally or alternatively be received fromany other suitable temperature sensors, such as temperature sensors ofthe RF communication system). The temperature information is preferablyprovided to the controller (e.g., to the control logic thereof, such asvia one or more ADCs).

S220 is preferably performed continuously, pseudo-continuously, orperiodically, but can additionally or alternatively be performedsporadically, be performed in response to trigger events, and/or beperformed with any other suitable timing.

However, S220 can additionally or alternatively include receiving anyother suitable temperature information in any other suitable mannerand/or with any other suitable timing.

4.3 Configuring Analog Taps

Configuring analog taps S230 preferably functions to configure tunableelements of the analog taps to provide desired filter enhancements. S230is preferably performed based on temperature information. S230 ispreferably performed in response to receiving the temperatureinformation (e.g., in S220). The temperature information is preferablyused as an input to one or more lookup tables (e.g., at the controller),wherein the tunable elements of the analog taps can be configured basedon the information stored in the lookup tables (e.g., informationassociated with the temperature information received).

S230 is preferably performed continuously, pseudo-continuously, and/orperiodically (e.g., with the same or similar timing as S220), but canadditionally or alternatively be performed sporadically, in response totrigger events (e.g., receipt of temperature information), and/or withany other suitable timing.

However, S230 can additionally or alternatively include configuring theanalog taps in any other suitable manner, and/or the method for filterenhancement can additionally or alternatively include any other suitableelements performed in any suitable manner.

Further, the method 200 can additionally or alternatively include anyother suitable elements performed in any suitable manner.

An alternative embodiment preferably implements some or all of the abovemethods in a computer-readable medium storing computer-readableinstructions. The instructions are preferably executed bycomputer-executable components preferably integrated with acommunication routing system. The computer-readable medium may be storedon any suitable computer readable media such as RAMs, ROMs, flashmemory, EEPROMs, optical devices (CD or DVD), hard drives, floppydrives, or any suitable device. The computer-executable component ispreferably a processor but the instructions may alternatively oradditionally be executed by any suitable dedicated hardware device.

Although omitted for conciseness, embodiments of the system and/ormethod can include every combination and permutation of the varioussystem components and the various method processes, wherein one or moreinstances of the method and/or processes described herein can beperformed asynchronously (e.g., sequentially), concurrently (e.g., inparallel), or in any other suitable order by and/or using one or moreinstances of the systems, elements, and/or entities described herein.

The FIGURES illustrate the architecture, functionality and operation ofpossible implementations of systems, methods and computer programproducts according to preferred embodiments, example configurations, andvariations thereof. In this regard, each block in the flowchart or blockdiagrams may represent a module, segment, step, or portion of code,which comprises one or more executable instructions for implementing thespecified logical function(s). It should also be noted that, in somealternative implementations, the functions noted in the block can occurout of the order noted in the FIGURES. For example, two blocks shown insuccession may, in fact, be executed substantially concurrently, or theblocks may sometimes be executed in the reverse order, depending uponthe functionality involved. It will also be noted that each block of theblock diagrams and/or flowchart illustration, and combinations of blocksin the block diagrams and/or flowchart illustration, can be implementedby special purpose hardware-based systems that perform the specifiedfunctions or acts, or combinations of special purpose hardware andcomputer instructions.

As a person skilled in the art will recognize from the previous detaileddescription and from the figures and claims, modifications and changescan be made to the preferred embodiments of the invention withoutdeparting from the scope of this invention defined in the followingclaims.

We claim:
 1. A system for filter enhancement, the system configured tobe electrically coupled in parallel with a filter, the systemcomprising: an analog tap comprising: a variable attenuator; a variablephase shifter; and a delay; wherein the variable attenuator, thevariable phase shifter, and the delay are electrically coupled in aseries arrangement; and a controller operable to: receive a temperaturemeasurement; and control the analog tap based on the temperaturemeasurement, comprising dynamically tuning the variable attenuator andthe variable phase shifter based on the temperature measurement.
 2. Thesystem of claim 1, wherein the controller comprises a temperature sensoroperable to sample the temperature measurement.
 3. The system of claim2, wherein the controller further comprises: an analog-to-digitalconverter (ADC) configured to receive, from the temperature sensor, ananalog temperature signal indicative of the temperature measurement, andto convert the analog temperature signal into a digital temperaturesignal indicative of the temperature measurement; and a digital controlcircuit configured to receive the digital temperature signal from theADC and to determine, based on the digital temperature signal, a set ofcontrol signals operable to control the analog tap.
 4. The system ofclaim 3, wherein the digital control circuit comprises memory thatstores a lookup table, wherein the lookup table is indexed based on atemperature index and stores values associated with the control signals.5. The system of claim 4, wherein the memory is one-time programmablememory, wherein the digital control circuit is further configured todetermine the temperature index based on the digital temperature signaland a temperature offset value.
 6. The system of claim 2, wherein theanalog tap and the temperature sensor are collocated within anintegrated circuit package.
 7. The system of claim 1, wherein the delayis a switchable delay.
 8. The system of claim 7, wherein the switchabledelay defines a delay input and a delay output, the switchable delaycomprising: a first delay segment defining a first delay input end, afirst delay output end, and a first delay time; a first bypass segmentdefining a first bypass input end and a first bypass output end, thefirst bypass output end electrically coupled to the delay output, thefirst bypass segment arranged electrically in parallel with the firstdelay segment; a first switch operable to electrically connect the delayinput to the first delay input end; a second switch operable toelectrically connect the delay input to the first bypass input end; anda third switch operable to electrically connect the first delay outputend to the first bypass output end.
 9. The system of claim 8, whereinthe switchable delay further comprises: a second delay segment defininga second delay input end, a second delay output end, and a second delaytime; a second bypass segment defining a second bypass input end and asecond bypass output end, the second bypass output end electricallycoupled to the delay output, the second bypass segment arrangedelectrically in parallel with the second delay segment; a fourth switchoperable to electrically connect the first bypass output end to thesecond delay input end; a fifth switch operable to electrically connectthe first bypass output end to the second bypass input end; and a sixthswitch operable to electrically connect the second delay output end tothe second bypass output end.
 10. The system of claim 9, wherein thefirst delay time is substantially different from the second delay time.11. system of claim 7, wherein the controller is further operable todynamically configure the switchable delay.
 12. The system of claim 1,wherein the analog tap further comprises a coupling tuner electricallycoupled in series with the variable attenuator, the variable phaseshifter, and the delay.
 13. The system of claim 1, wherein: the analogtap further comprises a tap filter electrically coupled in series withthe variable attenuator, the variable phase shifter, and the delay; thetap filter defines a filter slope and a cutoff frequency, wherein thetap filter is operable to vary the filter slope and the cutofffrequency; and controlling the analog tap based on the temperaturemeasurement further comprises, based on the temperature measurement,dynamically tuning at least one of the filter slope or the cutofffrequency.
 14. The system of claim 1, wherein: the analog tap furthercomprises a tap filter electrically coupled in series with the variableattenuator, the variable phase shifter, and the delay, the tap filterdefining a first cutoff frequency; the system further comprises a secondanalog tap electrically connected in parallel with the analog tap, thesecond analog tap comprising: a second variable phase shifter; and asecond tap filter electrically connected in series with the secondvariable phase shifter, the second tap filter defining a second cutofffrequency; and the controller is further operable to dynamically tunethe second variable phase shifter.
 15. The system of claim 14, wherein:the first tap filter comprises a low-pass filter; and the second tapfilter comprises a high-pass filter.
 16. The system of claim 14,wherein: the second analog tap further comprises: a second variableattenuator electrically connected in series with the second variablephase shifter; and a second delay electrically connected in series withthe second variable phase shifter and the second variable attenuator;the system further comprises a variable coupling tuner electricallyconnected in series with either the analog tap or the second analog tap;and the controller is further operable to dynamically tune the secondvariable attenuator and the variable coupling tuner.
 17. A filter systemcomprising: a radio frequency (RF) filter electrically coupled along aprimary signal path; an analog tap electrically coupled to the primarysignal path in parallel with the RF filter, the analog tap comprising aset of RF components electrically coupled in a series arrangement, theset of RF components comprising: an attenuator; a phase shifter; and adelay; wherein at least one RF component of the set is operable to bedynamically tuned; and a controller configured to dynamically tune theat least one RF component of the set based on a performancecharacteristic associated with the RF filter.
 18. The system of claim17, wherein the RF filter comprises at least one of: a bulk acousticwave filter, a surface acoustic wave filter, or a ceramic filter. 19.The system of claim 17, further comprising a second analog tapelectrically coupled to the primary signal path in parallel with the RFfilter and the analog tap, the second analog tap comprising a second setof RF components electrically coupled in a second series arrangement,the second set of RF components comprising: a second attenuator; and asecond phase shifter; wherein: at least one RF component of the secondset is operable to be dynamically tuned; and the controller is furtherconfigured to dynamically tune the at least one RF component of thesecond set based on a second performance characteristic associated withthe RF filter.
 20. The system of claim 19, wherein the secondperformance characteristic is the performance characteristic.
 21. Thesystem of claim 17, further comprises a temperature sensor configured tosample a temperature of the system and provide information indicative ofthe temperature to the controller, wherein the performancecharacteristic is the temperature.